Possible Alternator Problem???
Thread Starter
Team Owner
Joined: Jan 2006
Posts: 58,551
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From: The warm part of Anger Island
St. Jude Donor '09
Possible Alternator Problem???
I've started getting the "Service Charging System" message on the DIC pretty much any time I come to a stop over the last day or two and can't isolate the issue.
When Vette is cold it puts out 14.0 volts at idle. When it warms up it will drop down to the low 11-ish range and sometimes dip into the 10's. I took the belt off and notice a little bit of play in the pulley. It wiggles back and forth (in/out) just a bit.
When I'm driving the display reads that the battery volts are at 13.8-14.0. When i hit a stop light then all the "dummy signals" and messages start going off.
I've checked all the wiring going from the battery/alternator to the starter, cleaned them, and tightened them so I don't think that's the problem. Charging tests at the stealerships and auto parts stores say there is no problem. Is it worth taking the alternator off for a bench test or should I be looking else where for the problem?
When Vette is cold it puts out 14.0 volts at idle. When it warms up it will drop down to the low 11-ish range and sometimes dip into the 10's. I took the belt off and notice a little bit of play in the pulley. It wiggles back and forth (in/out) just a bit.
When I'm driving the display reads that the battery volts are at 13.8-14.0. When i hit a stop light then all the "dummy signals" and messages start going off.
I've checked all the wiring going from the battery/alternator to the starter, cleaned them, and tightened them so I don't think that's the problem. Charging tests at the stealerships and auto parts stores say there is no problem. Is it worth taking the alternator off for a bench test or should I be looking else where for the problem?
Safety Car
Joined: Jan 2006
Posts: 3,940
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From: shavertown Pa.
The alternator is within range, are you running too many accessories like the rear window defogger and the mirror heaters and or seat heaters all at the same time?
Your battery may not be able to handel such a large draw, I would have the battery tested with a load test and see how that go's.
If the battery is suspect go for the optional battery with a higher amperage than you have now, I like to go with 1000 amp batterys when I replace them.
Your battery may not be able to handel such a large draw, I would have the battery tested with a load test and see how that go's.
If the battery is suspect go for the optional battery with a higher amperage than you have now, I like to go with 1000 amp batterys when I replace them.
Team Owner
Joined: Jul 2006
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From: Kannapolis NC
Check carefully the red wire connection on the starter (solenoid). If that connection is loose or corroded, you will get lots of these issues. That point is the distribution point between the alternator and battery. It will eventually not start intermittently. Be careful, that connection is at battery voltage all the time. A wrench can cause a short if touched to ground.
Team Owner
Joined: Mar 2008
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From: Southern Utah
If you have a friend with a C6, I would try putting his alternator in your car...its a 15 minute job and would tell the story...my bet is still that the alternator is bad. Many times an alternator that is going bad will test fine at higher rpms, but is unable to make voltage at idle. The most difficult time for an alternator is when the engine is at idle, because it is not getting enough spin to put out alot of current.
Thread Starter
Team Owner
Joined: Jan 2006
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From: The warm part of Anger Island
St. Jude Donor '09
Alternator tested good on the bench. All wires leading from the alternator and battery to the starter have good clean, tight, connections. I get this fault with ac, lights, radio, etc... all on or off. I'll check the battery to see if it's too weak.
Team Owner
Joined: Mar 2008
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From: Southern Utah
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Drifting
Joined: Jul 2007
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From: Massapequa NY
The bench only tests it at a running speed not at an idle speed. Your problem is at idle. It could be that something is drawing so much current that the alternator can't keep up with it when it is at idle, but it isn't the battery being 'too weak'. The alternator supplies all power needs when the car is running, not the battery.
Team Owner
Joined: Mar 2008
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From: Southern Utah
Race Director
Joined: Sep 2007
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From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Mine did that for a few days, then went into remission for two weeks before dying instantly. Had it checked twice on the car and once on the bench during the initial phase and proclaimed good each test.
Not saying it is the alternator, but if it is, a call to 818 442 9082 got me a new one shipped the same day for less than $200. No relationship, just great service and good prices.
Not saying it is the alternator, but if it is, a call to 818 442 9082 got me a new one shipped the same day for less than $200. No relationship, just great service and good prices.
Safety Car
Joined: Dec 2007
Posts: 4,974
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From: Magnolia Texas
make sure you have the belt at the appropriate tension. had a similar issue with low output at idle and found a weak tensioner was letting belt slip. when under power, the engine movement was enough to tighten it back up. just a thought!
Thread Starter
Team Owner
Joined: Jan 2006
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From: The warm part of Anger Island
St. Jude Donor '09
I have another thread about the fan always being on even when the car is cold and the A/C is off. I'm wondering if this cold be part of the problem?
Drifting
Joined: Jul 2007
Posts: 1,454
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From: Massapequa NY
Belt is fine and so is the tension. I started it cold with battery fully charged and it was putting out 14.0v. As the car warmed up the volts went down and the "Service Charging System" warning came back on... even when the car was hovering around 12.5-13.0 volts. The car idles around 600rpm.
I have another thread about the fan always being on even when the car is cold and the A/C is off. I'm wondering if this cold be part of the problem?
I have another thread about the fan always being on even when the car is cold and the A/C is off. I'm wondering if this cold be part of the problem?
By any chance have you changed your spark plugs to non oem????
Thread Starter
Team Owner
Joined: Jan 2006
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From: The warm part of Anger Island
St. Jude Donor '09
Well, everything goes to normal when I pull the 60a fuse for teh cooling fan. Hmm... my fan is always on. I think my cooling fan module is bad since the problem goes away when I take it out of the equation and all of the wires/plugs going to it are clean with no tears, rips, or breaks.
Team Owner
Joined: Jun 2005
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From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
You could be right, but what happens in the summer when the cooling fans are on for good reason? Will you have the same warnings then? I might add, I thought the charging system indicated higher than 14.0; mine does and always has (14.2, 14.3 at times).
Thread Starter
Team Owner
Joined: Jan 2006
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From: The warm part of Anger Island
St. Jude Donor '09
When the fan comes on fine, but it's always on. I think there may be a short somewhere in that module drawing 2 volts constantly and it gets worse when it heats up. I've checked everywhere and it looks like only the stealership has this part
Drifting
Joined: Jul 2007
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From: Massapequa NY
Or it could be that the module being defective is drawing excessive current in the states that it is in......
Melting Slicks
Joined: Oct 2008
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From: Beverly Hills, MI
Just my 2 cents....